In typical automated stock control systems, a housing comprises a plurality of latched drawers. Articles to be supplied to users are provided in the drawers or compartments of the drawers. Examples of such articles include cutting tools and the like used with machine tools; other manufacturing tools and components; drugs, needles and other medical items; and legal documents. A control system allows a user to access the required article by unlatching the drawer containing the required article. The drawer is then pulled out from the home position (where no compartments are exposed) to the extent that the compartment containing the article is exposed, when the drawer is latched again to prevent further opening of the drawer. Such systems require complicated mechanisms for locking drawers closed in their home position, for unlocking the correct drawer and for allowing only that drawer to be opened, and then only to the extent that the required article is accessible.
In a known system, several trays are provided above one another in a housing, with each tray extending in the width direction of the housing. One or a number of drawers are provided on top of each tray, and a separate latch mechanism with separate control circuitry is provided in each tray for each drawer in that tray. In this system, it is not possible to remove individual drawers without removing the whole tray. Thus, restocking is generally carried out by opening the drawers and refilling the individual compartments. Moreover, modification of the layout of the drawers is often not easily practicable, with modified systems requiring the trays and housings to be redesigned and then built from scratch.
In other systems, drawers can only be removed by accessing the rear of the housing to release the drawers. In still other systems, drawers are removably dropped into movable carriers, with the movable carriers holding control electronics. Again, access to the rear of the housing is required to release drawers from carriers.
In general, improvements in the art have concentrated on the trays and drawer carriers. The prior art systems suffer the common problem that modification to meet particular customer needs, for example by resizing and reconfiguring drawers, is difficult and expensive. Moreover, the drawers cannot easily be removed for restocking or replacement. A further common problem is that the requirement to provide trays or movable carriers takes a large amount of space so that the systems have low storage density—in other words, the ratio of the usable storage volume to the volume of the apparatus as a whole is low. A yet further common problem is that current systems are expensive to manufacture.